There are a number of present keyboard designs that have certain ergonomic features, i.e., features designed and arranged for use by people so that people can interact most efficiently and safely with those features; however, in some cases, such keyboard designs are based on research that is twenty or more years old. See, e.g., M. Nakaseko, E. GrandJean and W. Hunting's “Studies on Ergonomically Designed Alphanumeric Keyboards,” The Human Factors Society, Human Factors 175-187 (1985), upon which the ergonomic Microsoft® Natural Keyboard shown in FIG. 1A is based in part.
Ergonomic keyboards thus include structures that are well suited for human preferences as they relate to the peculiar angles and structures of human arms, wrists and hands. For examples of existing ergonomic features, some existing keyboard designs employ a “fixed split ergonomic” keyboard design, wherein the main alphanumeric keys are split into two sections that are angled to be more in keeping with the angles made by the typical arms/wrists/hands of a keyboard user. Such a split design is exemplified by the Microsoft® Natural keyboard (hereinafter the “Natural keyboard” design) as well as other products which follow similar, if not identical, presentation of split keyboard typing areas. The halves H1 and H2 of the exemplary Natural keyboard illustrated in FIG. 1A show the split design of the alphanumeric keys.
As illustrated by FIGS. 1A and 1B, the Natural keyboard is defined by geometries of the split keyboard halves as well as geometries of the keyboard as a whole and in part with respect to various subparts. In terms of the split halves, the main QWERTY typing section is “split” into two halves H1 and H2, each of which is split open at a 12 or 12.5 degree angle for a total split open of 24 or 25 degrees, as illustrated in FIG. 1A.
The two halves H1 and H2 are also vertically tented, or gabled, at an 8 degree angle as illustrated by the isolated side view of a single row of the two halves H1 and H2 of the exemplary Natural keyboard, depicting the presentation of a classical QWERTY row including the keys: Caps Lock, A, S, D, F, G (half H1) and H, J, K, L, ;, ' and Enter (half H2). In this regard, as shown in FIG. 1B, the keys of the two halves of the Natural keyboard are kept on the same plane such that one planar surface is offered for all keys on that surface. In this regard, all of the keys of half HI are presented or positioned on plane P1 (side view shown defined by the line) and all of the keys of half H2 are presented or positioned on plane P2 (side view shown defined by the line).
Additionally, the orientation of an exemplary Natural keyboard NKB as a whole when presented as a surface to a user is such that the keyboard orientation KO may be presented both “flat” (0 degrees to a surface S) as illustrated in FIG. 1C, as well as with a “positive” slope (between 5 and 15 degrees to surface S) as illustrated in FIGS. 1D and 1E. A wrist rest WR may also be included as a part of the keyboard where a user's wrists tend to naturally rest, which may or may not slope along with the rest of the keyboard as shown in FIGS. 1D and 1E, respectively. Such a forward slope of whole keyboard is generally accomplished by the provision of mechanical mechanisms underneath the keyboard body, towards the rear of the keyboard, as shown by exemplary mechanical means MM, such as feet or legs, etc.
As mentioned, the Natural keyboard comes with or without a wrist rest WR (sometimes also called a palm rest). The palm rest may be “fixed” or “removable” in design. In existing designs, the height of the palm rest on Natural keyboard is at the same height as the front edge of the keyboard itself, as illustrated in each of FIGS. 1C to 1E by the arrow to the front edge of the keyboard, showing that the wrist rest edge adjoins the keyboard edge at substantially the same height.
Vern Putz-Anderson et al.'s “Cumulative trauma disorders: A manual for musculoskeletal diseases of the upper limbs,” Taylor & Francis (1988) describes some typical motions that the hands undergo. For background purposes, such exemplary motions for a hand are shown and labeled in FIG. 1F, and include neutral position, extension, radial deviation, flexion, ulnar deviation and pinch.
The design goals for the Natural keyboard included improving wrist postures while typing: to reduce pronation, i.e., rotation of the hand and forearm so that the palm faces inwards or downwards (twisting palm over), accomplished in part by the above-described 8 degree gable angle and reducing extension (bending hand backwards) accomplished in part by the above-described whole keyboard slope adjustments and the presence of a fixed palm rest; and reducing ulnar deviation (twisting hand towards little finger) accomplished by the above-described split angle of the two keyboard halves.
While the above mentioned features of the Natural keyboard were an improvement over preexisting keyboards, which tended to place more consideration on the functionality enabled by the keys, further ergonomic improvements are desired over the current Natural keyboard.